The goal was to see whether ketamine increased the ‘motivation to quit’ crack. But Dakwar et al also used questionnaires to formally assess the psychoactive effects. The key finding was that both doses of ketamine caused much stronger ‘mystical experiences’ than lorazepam, as measured with the HMS scale. Participants reported feeling “a new view of reality”, “incapable of being expressed in words”, “a feeling of awe”… pretty impressive, basically.

Furthermore, there was a strong correlation between the intensity of the injection-induced mystical experience, and subsequent motivation to quit. This is consistent with (although not proof of) the idea that the clinical effect of ketamine in addiction is an indirect effect of its psychoactive properties, rather than a direct pharmacological effect.